Methods of making a homologous series of compounds, or the testing of new potential drug compounds comprising a series of light compounds, has been a slow process because each member of a series or each potential drug must be made individually and tested individually. For example, a plurality of potential drug compounds is tested by an agent to test a plurality of materials that differ perhaps only by a single amino acid or nucleotide base, or a different sequence of amino acids or nucleotides.
The processes described above have been improved by microfluidic chips which are able to separate materials in a micro channel and move the materials through the micro channel is possible. Moving the materials through micro channels is possible by use of various electro-kinetic processes such as electrophoresis or electro-osmosis. Fluids may be propelled through various small channels by the electro-osmotic forces. An electro-osmotic force is built up in the channel via surface charge buildup by means of an external voltage that can repel fluid and cause flow.
In fluid delivery in microfluidic structures, it is important to distribute approximately the same fluid volume to each reaction well. By using certain fluids, however, even distribution to the various reaction wells is difficult to accomplish. This is especially true in pressure pumping. Pressure pumping uses pressurized fluid at the fluid input. The fluid under pressure is distributed along the channels and ultimately to reaction wells. One problem associated with pressure pumping is that fluid closer to the input is under higher pressure than the fluid further downstream due to the pressure losses associated with each of the branches. This in time allows the channels closer to the fluid input to fill more rapidly.